Many combat Veterans suffer from posttraumatic stress disorder (PTSD), an anxiety disorder that develops after an extremely stressful event or events. PTSD is associated with problems falling asleep or staying asleep. Veterans with PTSD also commonly have nightmares from stressful experiences. These symptoms can cause problems in daily life. Behavioral treatments that do not involve taking medication have been shown to help improve problems related to sleep and nightmares. However, very few of these treatments address both sleep problems and nightmares at the same time, even though many people suffer from both problems. The purpose of this study is to examine the effectiveness of a combined treatment for sleep problems and nightmares in Veterans suffering from combat-related PTSD that is presented in a group format. The investigators hypothesize that the completion of this treatment will lead to increases in sleep quality and decreases in the frequency and severity of nightmares as measured by standard questionnaires.